Fibroblast Growth Factor 21 Research Articles

Methionine Restriction Alleviates Diabetes-Associated Cognitive Impairment via Activation of FGF21

Glucose metabolism disturbances may result in diabetes-associated cognitive decline (DACI). Methionine restriction (MR) diet has emerged as a potential dietary strategy for managing glucose homeostasis. However, the effects and underlying mechanisms of MR on DACI have not been fully elucidated. Here, we found that a 13-week MR (0.17% methionine, w/w) intervention starting at 8 weeks of age improved peripheral insulin sensitivity in male db/db mice, a model for type 2 diabetes. Notably, MR significantly improved working as well as long-term memory in db/db mice, accompanied by increased PSD-95 level and reduced neuroinflammatory factors, malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). We speculate that this effect may be mediated by MR activating hepatic fibroblast growth factor 21 (FGF21) and the brain FGFR1/AMPK/GLUT4 signaling pathway to enhance brain glucose metabolism. To further delineate the mechanism, we used intracerebroventricular injection of adeno-associated virus to specifically knock down FGFR1 in the brain to verify the role of FGFR1 in MR-mediated DACI. It was found that the positive effects of MR on DACI were offset, reflected in decreased cognitive function, impaired synaptic plasticity, upregulated neuroinflammation, and balanced enzymes regulating reactive oxygen species (Sod1, Sod2, Nox4). Of note, the FGFR1/AMPK/GLUT4 signaling pathway and brain glucose metabolism were inhibited. In summary, our study demonstrated that MR increased peripheral insulin sensitivity, activated brain FGFR1/AMPK/GLUT4 signaling through FGF21, maintained normal glucose metabolism and redox balance in the brain, and thereby alleviated DACI. These results provide new insights into the effects of MR diet on cognitive dysfunction caused by impaired brain energy metabolism.

Activation of fibroblast growth factor 21 by Canagliflozin reduces high-fat diet associated obesity-related cardiac injury: a translational study from bench to bedside

Abstract Aims/hypothesis Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are indicated for the treatment of type 2 diabetes, and evidence shows that they may confer a cardioprotective effect to reduce the incidence of cardiovascular conditions in obese type 2 diabetes patients. The mechanisms underlying this effect remain unclear, but an SGLT2i, canagliflozin (CANA), has been reported to increase levels of fibroblast growth factor-21 (FGF21) and enhance activation of its downstream target proteins. We thus aimed to study whether the effect on FGF21 by CANA can reduce obesity-related cardiac injury. Methods 1) Animal study: Sixteen-week-old normal diet and high-fat diet male mice were treated with or without 30 mg/kg CANA once a day for 24 weeks, and were subsequently examined for body weight, blood glucose levels, adipose tissue changes, lipid accumulation in the liver, and cardiac function. 2) Cell study: An in vitro study that treated H9c2 cardiomyocyte cells cultured in a simulated high-lipid environment containing palmitic acid (PA) with FGF21 recombinant protein was also conducted to examine protein expression profiles. Furthermore, the effect of CANA on FGF21 expression. 3) Human clinical trial: A randomized double-blinded control trial (NCT 05764811) was performed to test effect of CANA on MRI liver fibrosis scores of obese type 2 diabetes patients (n = 40). Results 1) High-fat diet mice treated with CANA for 24 weeks had lower average body weight than untreated controls (34 g vs. 40 g, p < 0.001). In addition, CANA treatment stimulated FGF21 protein production in liver tissue and plasma at higher levels for both normal diet and high-fat diet mice, and reduced expression levels of proteins associated with fibrosis and apoptosis. 2) H9c2 cardiomyocyte culture studies suggested that a simulated high-lipid environment with PA caused higher expression of apoptotic proteins, but the addition of FGF21 recombinant protein significantly reduced apoptosis signalling. 3) MRI before and after 4 weeks of CANA treatment in obese type 2 diabetes patients showed a significant reduction in liver fibrosis scores for those receiving CANA treatment. Conclusion CANA treatment stimulated FGF21 protein expression and reduced fibrosis and apoptosis signalling protein expression. Moreover, reductions in liver fibrosis scores were observed in obese type 2 diabetes patients treated with CANA. Taken together, this suggests that CANA-induced FGF21 expression may exert a cardioprotective effect against fibrosis and apoptosis and can potentially reduce the risk of obesity-related cardiac injury.

Cordycepin Activates Autophagy to Suppress FGF9-induced TM3 Mouse Leydig Progenitor Cell Proliferation.

Fibroblast growth factor 9 (FGF9) is a member of the human FGF family known for its pivotal roles in various biological processes, such as cell proliferation, tissue repair, and male sex determination including testis formation. Cordycepin, a bioactive compound found in Cordyceps sinensis, exhibits potent antitumor effects by triggering apoptosis and/or autophagy pathways. Our research has unveiled that FGF9 promotes proliferation and tumorigenesis in MA-10 mouse Leydig tumor cells, as the phenomena are effectively countered by cordycepin through apoptosis induction. Moreover, we have observed FGF9-mediated stimulation of proliferation and tumorigenesis in TM3 mouse Leydig progenitor cells, prompting an investigation into the potential inhibitory effect of cordycepin on TM3 cell proliferation under FGF9 treatment. Hence, we hypothesized that cordycepin induces cell death via apoptosis and/or autophagy in FGF9-treated TM3 cells. TM3 cells were treated with cordycepin and/or FGF9, and the flow cytometry, immunofluorescent plus western blotting assays were used to determine how cordycepin regulated Leydig cell death under FGF9 treatment. Our findings reveal that cordycepin restricts cell viability and colony formation while inducing morphological alterations associated with cell death in FGF9-treated TM3 cells. Surprisingly, cordycepin fails to elicit the expression of key apoptotic markers, suggesting an alternate mechanism of action. Although the expression of certain autophagy-related proteins remains unaltered, a significant up-regulation of LC3-II, indicative of autophagy, is observed in cordycepin-treated TM3 cells under FGF9 influence. Moreover, the inhibition of autophagy by chloroquine reverses cordycepin-induced TM3 cell death, highlighting the crucial role of autophagy in this process. Our study demonstrates that cordycepin activates autophagy to induce cell death in TM3 cells under FGF9 treatment conditions.

Therapeutic effects of FGF21 mimetic bFKB1 on MASH and atherosclerosis in Ldlr-/-.Leiden mice.

Fibroblast growth factor 21 (FGF21) is a promising target for treatment of obesity-associated diseases including metabolic dysfunction-associated steatohepatitis (MASH) and atherosclerosis. We evaluated the effects of the bispecific anti-FGF21-β klotho (KLB) agonist antibody bFKB1 in a preclinical model of MASH and atherosclerosis. Low-density lipoprotein receptor knockout (Ldlr-/-).Leiden mice received a high-fat diet for 20 weeks, followed by treatment with an isotype control antibody or bFKB1 for 12 weeks. Effects on plasma risk markers and (histo)pathology of liver, adipose tissue, and heart were evaluated alongside hepatic transcriptomics analysis. bFKB1 lowered body weight (-21%) and adipose tissue mass (-22%) without reducing food intake. The treatment also improved plasma insulin (-80%), cholesterol (-48%), triglycerides (-76%), alanine transaminase (ALT: -79%), and liver weight (-43%). Hepatic steatosis and inflammation were strongly reduced (macrovesicular steatosis -34%; microvesicular steatosis -100%; inflammation -74%) and while the total amount of fibrosis was not affected, bFKB1 did decrease new collagen formation (-49%). Correspondingly, hepatic transcriptomics and pathway analysis revealed the mechanistic background underlying these histological improvements, demonstrating broad inactivation of inflammatory and profibrotic transcriptional programs by bFKB1. In epididymal white adipose tissue, bFKB1 reduced adipocyte size (-16%) and inflammation (-52%) and induced browning, signified by increased uncoupling protein-1 (UCP1) protein expression (8.5-fold increase). In the vasculature, bFKB1 had anti-atherogenic effects, lowering total atherosclerotic lesion area (-38%). bFKB1 has strong beneficial metabolic effects associated with a reduction in hepatic steatosis, inflammation, and atherosclerosis. Analysis of new collagen formation and profibrotic transcriptional programs indicate that bFKB1 treatment may have antifibrotic potential in a longer treatment duration as well.

Compromised macrophages contribute to progression of MASH to hepatocellular carcinoma in FGF21KO mice.

Metabolic dysfunction-associated steatohepatitis is well accepted as a potential precursor of hepatocellular carcinoma. Previously, we reported that fibroblast growth factor 21 (FGF21) revealed a novel anti-inflammatory activity via inhibiting the TLR4-IL-17A signaling, which could be a potential anticarcinogenetic mechanism to prevent to MASH-HCC transition. Here, we set out to determine whether FGF21 has a major impact on Kupffer cells' (KCs) ability during MASH-HCC transition. We found aberrant hepatic FGF21 and KC pool in human MASH-HCC. Lack of FGF21 up-regulated ALOX15, which converted the oxidized fatty acids to induce excessive KC death and mobilization of monocyte-derived macrophages (MoMFs) for KC replacement. Lack of FGF21 oversupplied free fatty acids for sphingosine-1-phosphate (S1P) cascade synthesis to mediate MASH-HCC transition via S1P-YAP signaling and cross-talk between tumor cells and macrophages. In conclusion, lack of FGF21 accelerated MASH-HCC transition via the S1P-AP signaling. Compromised MoMFs could present as tumor-associated macrophage phenotype rendering tumor immune microenvironment for MASH-HCC transition.

Low Serum Fibroblast Growth Factor 21 Level and Its Altered Regulation by Thyroid Hormones in Patients with Hashimoto's Thyroiditis on Levothyroxine Substitution.

Fibroblast growth factor 21 (FGF21) is a hormonal regulator of lipid and glucose metabolism exerting protection against atherosclerosis by multiple actions on the blood vessels, liver, and adipose tissues. We aimed to investigate serum FGF21 level and its relation to thyroid hormones and metabolic parameters among patients with Hashimoto's thyroiditis (HT). Eighty patients with HT on levothyroxine treatment and eighty-two age- and BMI-matched adults without thyroid disease serving as controls were enrolled. Serum FGF21 concentrations were determined with an enzyme-linked immunosorbent assay. Median serum FGF21 level was significantly lower in HT patients compared with controls (74.2 (33.4-148.3) pg/mL vs. 131.9 (44.8-236.3) pg/mL; p = 0.03). We found a positive correlation between FGF21 and age, triglyceride, total cholesterol, and low-density lipoprotein cholesterol in both groups, while thyroid stimulating hormone and C-reactive protein showed a positive correlation, and thyroxine had an inverse correlation with FGF21 only in control subjects. According to multiple regression analyses, thyroid status is the main predictor of FGF21 in healthy controls, while it is not a significant predictor of FGF21 among HT patients on levothyroxine supplementation therapy. Our results indicate that the physiological role of thyroid function in the regulation of FGF21 synthesis is impaired in HT patients, which may contribute to the metabolic alterations characteristic of HT patients.

Distinct genetic signals at the FGF21 locus complicate studies of FGF21's role in diet regulation using human cohort data

ObjectivesExperimental and genetic studies suggest that fibroblast growth factor 21 (FGF21) modulates macronutrient and alcohol preferences, but evidence of such regulation in humans remains scarce. To address this gap in translation, we aimed to map the relationships between plasma FGF21 levels, FGF21 genetic variation and habitual macronutrient intake in a large human population. MethodsWe fine-mapped and performed colocalization of the FGF21 genetic region in GWAS summary statistics of plasma FGF21 levels and macronutrient intake. UK Biobank data were used to investigate the associations between FGF21 genetic variants, plasma FGF21 protein levels, and macronutrient intake (including alcohol) assessed with repeated 24-hour recalls. One- and two-sample mendelian randomization were performed to estimate the effects of plasma FGF21 on macronutrient intake. ResultsWe show that the main macronutrient-associated variant rs838133 and the FGF21 cis-pQTL rs838131, both in the FGF21 gene, are distinct genetic signals. Effect directions also suggest that the influence of FGF21 variation on macronutrient intake appear more complex than by direct mediation through plasma FGF21. Only when considering this complexity at FGF21, is plasma FGF21 estimated to reduce alcohol and increase protein and fat intake using mendelian randomization. Importantly, plasma FGF21 levels also appear markedly elevated by primarily high alcohol and low protein intake. ConclusionsThese findings support the feedback diet-regulatory mechanism of FGF21 in humans, but highlights the need for mechanistic characterization of the complex FGF21 genetic region.

Fibroblast growth factor 21: update on genetics and molecular biology.

Since its discovery, most research on fibroblast growth factor 21 (FGF21) has focused on its antihyperglycemia properties. However, attention has recently shifted towards elucidating the ability of FGF21 to lower circulating lipid levels and ameliorate liver inflammation and steatosis. We here discuss the physiology of FGF21 and its role in lipid metabolism, with a focus on genetics, which has up until now not been fully appreciated. New developments have uncovered associations of common small-effect variants of the FGF21 gene, such as the single nucleotide polymorphisms rs2548957 and rs838133, with numerous physiological, biochemical and behavioural phenotypes linked to energy metabolism and liver function. In addition, rare loss-of-function variants of the cellular receptors for FGF21 have been recently associated with severe endocrine and metabolic phenotypes. These associations corroborate the findings from basic studies and preliminary clinical investigations into the therapeutic potential of FGF21 for the treatment of metabolic dysfunction-associated steatotic liver disease (MASLD) and hypertriglyceridemia. Furthermore, recent breakthrough research has begun to dissect mechanisms of a potential FGF21 brain-adipose axis. Such inter-organ communication would be comparable to that seen with other potent metabolic hormones. A deeper understanding of FGF21 could prove to be further beneficial for drug development. FGF21 is a potent regulator of lipid and energy homeostasis and its physiology is currently at the centre of investigative efforts to develop agents targeting hypertriglyceridemia and MASLD.

From a solitary blood-derived biomarker to combined biomarkers of sarcopenia: Experiences from the Korean Frailty and Aging Cohort Study.

Sarcopenia is recognized as a complex and multifactorial disorder that includes nutritional deficiency, inactivity, proinflammatory status, hormonal changes, neurological degeneration, and metabolic disturbances. Its' pathogenesis is not fully understood. Therefore, identifying specific biomarkers of sarcopenia will help us understand its pathophysiology. The most frequently reported blood-derived biomarkers of sarcopenia are growth factors, neuromuscular junctions, endocrine systems, mitochondrial dysfunction, inflammation-mediated and redox processes, muscle protein turnover, blood metabolomics, and behavior-mediated biomarkers. Here, we address the implications of sarcopenia biomarkers based on our research experience with KFACS cohort data. It includes free testosterone, myostatin, fibroblast growth factor 21 (FGF-21), growth differentiation factor 15 (GDF-15), procollagen type III N-terminal peptide (P3NP), creatinine-based biomarkers, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), brain-derived neurotrophic factor (BDNF), metabolites (proline, alanine, tryptophan), and multi-biomarker risk score. We attempted to explain the paradoxical findings of myostatin and FGF-21 levels in relation to sarcopenia. GDF-15 levels were associated with sarcopenia prevalence but not its incidence. Plasma P3NP and BDNF levels may be biomarkers of muscle quality rather than quantity. Lower erythrocyte EPA and DHA levels were associated with slow gait speed, and erythrocyte EPA levels were associated with low handgrip strength. We developed a multi-biomarker risk score for sarcopenia and found that its accuracy in diagnosing sarcopenia was higher than that of any single biomarker.

Metabolic Syndrome, Adipokines, and Response to Advanced Therapies in Rheumatoid Arthritis.

We determined if metabolic syndrome, its components, and adipokines (adiponectin, leptin, Fibroblast Growth Factor-21) were associated with response to advanced therapies among patients with rheumatoid arthritis (RA). This study included participants with RA initiating either TNFi or non-TNFi biologic therapies from the Comparative Effectiveness Registry to studyTherapies forArthritis andInflammatory Conditions(CERTAIN) cohort within the CorEvitas registry. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III definition. Adipokines were assessed on stored samples from a sub-sample of responders and non-responders (N=200). The primary outcome was the achievement of a change as large as the minimal clinically important difference (MCID) for the Clinical Disease Activity Index (CDAI) at 6 months. Among 2,368 participants, 687 (29%) had metabolic syndrome. Metabolic syndrome was associated with lower odds of achieving CDAI MCID [OR (95% CI): 0.69 (0.56,0.86) p=0.001] with a dose-dependent decrease in response rate according to the number of components present. Model fit was superior for metabolic syndrome compared to BMI. Associations between metabolic syndrome and MCID achievement were similar between patients receiving TNFi [OR (95% CI): 0.65 (0.49,0.87) p=0.003] v. non-TNF therapies [OR (95% CI): 0.76 (0.55,1.04) p=0.08)] (p-for-interaction=0.49). Adipokines were not associated with MCID achievement. Metabolic syndrome is associated with lower response rates with the initiation of an advanced therapy in RA, with similar effects for both TNFi and non-TNFi agents. Adipokines were strongly associated with metabolic syndrome but were not associated with clinical response.

Adipokine/hepatokines profiling of fatty liver in adolescents and young adults: cross-sectional and prospective analyses of the BCAMS study.

The underlying connections between obesity and non-alcoholic fatty liver disease (NAFLD) are not fully understood. One potential link might be the imbalanced adipokines and hepatokines. We aimed to explore the associations between specific adipokines/hepatokines and NAFLD in Chinese youth and to determine how these biomarkers mediate the obesity-NAFLD relationship. We analyzed data from the 10-year follow-up visit of the Beijing Children and Adolescents Metabolic Syndrome (BCAMS) study (n = 509; mean age = 20.2years) for a comprehensive metabolic risk assessment, including liver ultrasound and plasma measurements of adiponectin, leptin, fibroblast growth factor 21 (FGF21), retinol-binding protein 4 (RBP4), and angiopoietin-like protein 8 (ANGPTL8). Longitudinal analysis was performed on a subgroup (n = 307), with complete baseline (mean age = 12.2years) and follow-up data. Mediation models assessed how obesity at baseline and follow-up influence NAFLD through these biomarkers. Participants with NAFLD exhibited a high prevalence of central obesity (90.9%). Both cross-sectional and prospective analyses identified increased RBP4, FGF21, leptin, and decreased adiponectin levels as significant predictors of NAFLD. More adipokine/hepatokine abnormalities were linked to higher NAFLD risk. Furthermore, ratios reflecting adipokine/hepatokine imbalances, including leptin/adiponectin, FGF21/adiponectin, and RBP4/adiponectin, demonstrated stepwise changes correlating with NAFLD severity (all p < 0.05). Mediation analysis indicated that these four adipokines/hepatokines accounted for approximately 72.4% of the central obesity-NAFLD relationship and 80.1% in the subgroup analysis using baseline childhood data. Dysregulated adipokines/hepatokines may explain the onset or progression of obesity-related NAFLD in youths. Higher RBP4, FGF21 and leptin, alongside lower adiponectin, could serve as early biomarkers for NAFLD.

Association of Low Vitamin D Status With Adiponectin and Fibroblast Growth Factor-21 in Newly Diagnosed Type 2 Diabetes Mellitus Patients

Association of Low Vitamin D Status With Adiponectin and Fibroblast Growth Factor-21 in Newly Diagnosed Type 2 Diabetes Mellitus Patients

Exploring causal correlations between inflammatory cytokines and coronary heart disease: A Mendelian randomization study.

Coronary heart disease (CHD) is a global health concern, with inflammation significantly contributing to its pathogenesis. It is crucial to understand the relationship between inflammatory cytokines and CHD. This study investigates the causal correlations between circulating inflammatory cytokines and CHD using Mendelian randomization (MR), assessing both causative and resultant roles of these cytokines in CHD. In this bidirectional MR analysis, we used genetic data from a genome-wide association study (GWAS) of 60,801 CHD cases and 123,504 controls of European ancestry. We derived inflammatory cytokine data from a GWAS summary of 14,824 participants. The primary analytical approach was the inverse variance-weighted (IVW) method, supported by MR-Egger, weighted median, and weighted mode analyses. Heterogeneity was assessed using the Cochrane Q test, and horizontal pleiotropy was evaluated through the MR-Egger intercept and the MR-PRESSO global test, ensuring robustness against potential pleiotropic bias. This study pinpointed several cytokines as key upstream influencers on the risk of CHD, including eotaxin (CCL11) (odds ratio [OR]: 1.10, 95% confidence interval [CI]: 1.03-1.18, P = .003), C-C motif chemokine ligand 20 (CCL20) (OR: 1.15, 95% CI: 1.05-1.25, P = .002), macrophage colony-stimulating factor 1 (CSF1) (OR: 1.09, 95% CI: 1.01-1.17, P = .020), Fibroblast growth factor 21 (FGF21) (OR: 1.14, 95% CI: 1.01-1.29, P = .038), Fms-related tyrosine kinase 3 ligand (FLT3LG) (OR: 1.26, 95% CI: 1.09-1.44, P = .001), neurotrophin-3 (NT-3) (OR: 1.12, 95% CI: 1.01-1.24, P = .026), and leukemia inhibitory factor (LIF) (OR: 0.89, 95% CI: 0.80-0.99, P = .029). Conversely, T-cell surface glycoprotein CD5 (CD5) (beta: -0.15, 95% CI: -0.29 to -0.01, P = .042) were identified as downstream factors impacted by CHD. No evidence of heterogeneity or horizontal pleiotropy was detected across all results, and a leave-one-out analysis substantiated the robustness of these findings. These findings suggest that CCL11, CCL20, CSF1, FGF21, FLT3LG, NT-3, and LIF may play a crucial role in the pathogenesis of CHD. Additionally, CHD may impact the expression of CD5. Additional research is needed to explore the potential of these biomarkers in the prevention and treatment of CHD.

Hepatokines and MASLD: The GLP1-Ras-FGF21-Fetuin-A Crosstalk as a Therapeutic Target

The introduction of the term “Metabolic Steatotic Liver Disease” (MASLD) underscores the critical role of metabolic dysfunction in the development and progression of chronic liver disease and emphasizes the need for strategies that address both liver disease and its metabolic comorbidities. In recent years, a liver-focused perspective has revealed that altered endocrine function of the fatty liver is a key contributor to the metabolic dysregulation observed in MASLD. Due to its secretory capacity, the liver’s increased production of proteins known as “hepatokines” has been linked to the development of insulin resistance, explaining why MASLD often precedes dysfunction in other organs and ultimately contributes to systemic metabolic disease. Among these hepatokines, fibroblast growth factor 21 (FGF21) and fetuin-A play central roles in regulating the metabolic abnormalities associated with MASLD, explaining why their dysregulated secretion in response to metabolic stress has been implicated in the metabolic abnormalities of MASLD. This review postulates why their modulation by GLP1-Ras may mediate the beneficial metabolic effects of these drugs, which have increased attention to their emerging role as pharmacotherapy for MASLD. By discussing the crosstalk between GLP1-Ras-FGF21-fetuin-A, this review hypothesizes that the possible modulation of fetuin-A by the novel GLP1-FGF21 dual agonist pharmacotherapy may contribute to the management of metabolic and liver diseases. Although research is needed to go into the details of this crosstalk, this topic may help researchers explore the mechanisms by which this type of pharmacotherapy may manage the metabolic dysfunction of MASLD.

7492 Fibroblast Growth Factor 21 In The Diagnosis And Treatment Of Metabolic Disorders

Abstract Disclosure: H.M. Heshmati: None. H.S. Abu-Lebdeh: None. Background: Fibroblast growth factor 21 (FGF21), a member of the human FGF superfamily, is a 181 amino acid peptide hormone primarily produced by the liver. The gene of FGF21, located on chromosome 19, was cloned in 2000. FGF21 is involved in the maintenance of metabolic homeostasis. This review presents an update on the relevance of FGF21 in the diagnosis and treatment of metabolic disorders including obesity, nonalcoholic fatty liver disease (NAFLD), dyslipidemia, and type 2 diabetes. Methods: A systematic search of literature was conducted using the search terms fibroblast growth factor 21, obesity, nonalcoholic fatty liver disease, dyslipidemia, and type 2 diabetes. Results: FGF21 is a stress hormone with effects on energy expenditure and metabolism of lipids and glucose. FGF21 exerts its endocrine action in the central nervous system and adipose tissue. The serum FGF21 levels in normal subjects increase with aging. Stressful conditions (e.g., fasting status, protein restriction, exercise, metabolic disorders, kidney diseases, cardiovascular diseases, and sepsis) increase FGF21 secretion. Serum FGF21 levels are increased in obesity, NAFLD, dyslipidemia, and type 2 diabetes. Some of these patients may have a state of FGF21 resistance. The resistance to FGF21 is related, at least in part, to the presence of high circulating levels of fibroblast activation protein, a protease that inactivates FGF21. It has been suggested that the exercise-induced weight loss can be due to increased FGF21 secretion and decreased FGF21 resistance in adipose tissue. Serum FGF21 level has the potential to be used as a biomarker for early diagnosis of metabolic disorders (e.g., NAFLD and type 2 diabetes). Based on different metabolic properties of FGF21, FGF21-based therapy has been considered as an attractive approach for the treatment of metabolic disorders. Since native FGF21 has poor pharmacodynamic properties (e.g., short half-life and proteolytic cleavage by proteases), long-acting FGF21 analogs (e.g., LY2405319, PF-05231023, pegozafermin, AKR-001, and LLF580) have been synthesized and tested in clinical trials for the treatment of obesity, NAFLD, dyslipidemia, and type 2 diabetes. The available results show that FGF21 analogs can reduce body weight, liver fat, blood lipids, and fasting insulin/insulin resistance. Overall, the treatment with these analogs is safe and well tolerated. Conclusion: FGF21 is a predominantly liver-derived peptide hormone regulating energy expenditure and metabolism of lipids and glucose. Serum FGF21 levels are increased in several metabolic disorders including obesity, NAFLD, dyslipidemia, and type 2 diabetes. FGF21 is an attractive target for the treatment of these metabolic disorders. Despite some promising results observed with the use of FGF21 analogs, more clinical studies are needed before recommending FGF21-based therapies in metabolic disorders. Presentation: 6/2/2024

6420 Organokines and Liver Enzymes in Adolescent Girls with Polycystic Ovary Syndrome During Randomized Treatments

Abstract Disclosure: C. Garcia-Beltran: None. M. Peyrou: None. F.E. de Zegher: None. A. López-Bermejo: None. F. Villarroya: None. L. Ibanez: None. Introduction: Polycystic ovary syndrome (PCOS) is often related to metabolic associated fatty liver disease (MAFLD). MAFLD has been associated with altered hepatic function and systemic dysmetabolism and with abnormal circulating levels of signaling molecules, so-called organokines. Here, we assessed the effects of two randomized treatments on a set of organokines in adolescent girls with PCOS and without obesity, and report the associations with circulating biomarkers of liver damage which were assessed longitudinally in the aforementioned studies as safety markers. Materials and Methods: Liver enzymes [aspartate aminotransferase (AST), alanine amino transferase (ALT) and gamma-glutamyl transferase (GGT)] were assessed as safety markers in previous randomized pilot studies comparing the effects of an oral contraceptive (OC) to those of a low-dose combination of spironolactone-pioglitazone-metformin (spiomet) for 1 yr. As a post-hoc endpoint, the organokines fibroblast growth factor-21 (FGF21), diazepam-binding protein-1 (DBI) and meteorin-like protein (METRNL), were assessed by ELISA after 6 months on OC (N=26) or spiomet (N= 28). Auxological, endocrine-metabolic, body composition (by DXA) and abdominal fat partitioning (by MRI) were also evaluated. Healthy age-matched adolescent girls (N=17) served as controls. Results: Circulating ALT and GGT levels raised during OC treatment and returned to baseline concentrations in the post-treatment phase; in contrast, spiomet treatment elicited no detectable changes in ALT and GGT concentrations. In relation to organokines after 6 mo on treatment, (1) FGF21 levels were significantly higher in PCOS adolescents than in control girls; (2) DBI levels were lower in OC-treated girls as compared to controls and spiomet-treated girls; (3) no differences were observed in METRNL concentrations between PCOS girls and controls. Serum ALT and GGT levels directly correlated with circulating METRNL levels only in OC-treated girls (R=0.449; P=0.036 and R=0.552; P=0.004, respectively). Conclusion: The on-treatment increase in ALT and GGT levels occurring only in OC-treated girls associates with circulating METRNL levels suggesting an enhanced METRNL synthesis as a reaction to the hepatic changes elicited by OC treatment. Trial registration numbers: ISRCTN29234515 (https://doi.org/10.1186/ISRCTN29234515) and ISRCTN11062950 (https://doi.org/10.1186/ISRCTN11062950) Presentation: 6/2/2024

6420 Organokines and Liver Enzymes in Adolescent Girls with Polycystic Ovary Syndrome During Randomized Treatments

Abstract Disclosure: C. Garcia-Beltran: None. M. Peyrou: None. F.E. de Zegher: None. A. López-Bermejo: None. F. Villarroya: None. L. Ibanez: None. Introduction: Polycystic ovary syndrome (PCOS) is often related to metabolic associated fatty liver disease (MAFLD). MAFLD has been associated with altered hepatic function and systemic dysmetabolism and with abnormal circulating levels of signaling molecules, so-called organokines. Here, we assessed the effects of two randomized treatments on a set of organokines in adolescent girls with PCOS and without obesity, and report the associations with circulating biomarkers of liver damage which were assessed longitudinally in the aforementioned studies as safety markers. Materials and Methods: Liver enzymes [aspartate aminotransferase (AST), alanine amino transferase (ALT) and gamma-glutamyl transferase (GGT)] were assessed as safety markers in previous randomized pilot studies comparing the effects of an oral contraceptive (OC) to those of a low-dose combination of spironolactone-pioglitazone-metformin (spiomet) for 1 yr. As a post-hoc endpoint, the organokines fibroblast growth factor-21 (FGF21), diazepam-binding protein-1 (DBI) and meteorin-like protein (METRNL), were assessed by ELISA after 6 months on OC (N=26) or spiomet (N= 28). Auxological, endocrine-metabolic, body composition (by DXA) and abdominal fat partitioning (by MRI) were also evaluated. Healthy age-matched adolescent girls (N=17) served as controls. Results: Circulating ALT and GGT levels raised during OC treatment and returned to baseline concentrations in the post-treatment phase; in contrast, spiomet treatment elicited no detectable changes in ALT and GGT concentrations. In relation to organokines after 6 mo on treatment, (1) FGF21 levels were significantly higher in PCOS adolescents than in control girls; (2) DBI levels were lower in OC-treated girls as compared to controls and spiomet-treated girls; (3) no differences were observed in METRNL concentrations between PCOS girls and controls. Serum ALT and GGT levels directly correlated with circulating METRNL levels only in OC-treated girls (R=0.449; P=0.036 and R=0.552; P=0.004, respectively). Conclusion: The on-treatment increase in ALT and GGT levels occurring only in OC-treated girls associates with circulating METRNL levels suggesting an enhanced METRNL synthesis as a reaction to the hepatic changes elicited by OC treatment. Trial registration numbers: ISRCTN29234515 (https://doi.org/10.1186/ISRCTN29234515) and ISRCTN11062950 (https://doi.org/10.1186/ISRCTN11062950) Presentation: 6/2/2024

Targeted Therapy of Osteoarthritis via Intra-Articular Delivery of Lipid-Nanoparticle-Encapsulated Recombinant Human FGF18 mRNA.

Fibroblast growth factor 18 (FGF18) emerges as a promising therapeutic target for osteoarthritis (OA). In this study, a novel articular cavity-localized lipid nanoparticle (LNP) named WG-PL14 is developed. This optimized formulation has a nearly 30-fold increase in mRNA expression as well as better articular cavity enrichment compared to commercial lipids MC3 when performing intra-articular injection. Then, a mRNA sequence encoding recombinant human FGF18 (rhFGF18) for potential mRNA therapy in OA is optimized. In vitro assays confirm the translation of rhFGF18 mRNA into functional proteins within rat and human chondrocytes, promoting cell proliferation and extracellular matrix (ECM) synthesis. Subsequently, the therapeutic efficacy of the LNP-rhFGF18 mRNA complex is systematically assessed in a mouse OA model. The administration exhibits several positive outcomes, including an improved pain response, upregulation of ECM-related genes (e.g., AGRN and HAS2), and remodeling of subchondral bone homeostasis compared to a control group. Taken together, these findings underscore the potential of localized LNP-rhFGF18 mRNA therapy in promoting the regeneration of cartilage tissue and mitigating the progression of OA.

Fibroblast growth factor 21 attenuates pulmonary ischemia/reperfusion injury via inhibiting endoplasmic reticulum stress-induced ferroptosis though FGFR1/PPARδ signaling pathway

BackgroundAcute lung injury is a critical life-threatening complication of pulmonary and cardiac surgery with a high rate of morbidity and mortality. Fibroblast growth factor 21 (FGF21) has been reported to play an important role in protecting vital organs from damage. This study aims to investigate the potential protective role and mechanism of FGF21 in pulmonary ischemia/reperfusion (I/R)-induced acute lung injury. MethodsA pulmonary epithelial cell line was treated with hypoxia/regeneration (H/R) in vitro and a mouse model of acute lung injury was induced with pulmonary I/R in vivo. Lung injury after pulmonary I/R was compared between FGF21-konckout (KO) mice and wild-type (WT) mice. Recombinant FGF21 was administrated in vivo and in vitro to determine its therapeutic effect. ResultsCirculating levels of FGF21 in mice with pulmonary I/R injury were significantly higher than in those without pulmonary I/R injury. Lung injury was aggravated in FGF21-KO mice compared with WT mice and the administration of FGF21 alleviated lung injury in mouse treated with I/R and pulmonary epithelial cell injury treated with H/R. FGF21 treatment decreased endoplasmic reticulum (ER) stress, Fe2+ and lipid reactive oxygen species (ROS) contents and GPX4 expression and increased PTGS2 levels. Mechanistically, FGF21 upregulated the expression of FGFR1 and PPARδ, ameliorated ER stress and ER stress induced-ferroptosis. Furthermore, FGF21 increased the expression level of PPARδ in pulmonary epithelial cell exposed to H/R, which was inhibited by FGFR1 inhibitor (PD173074). The protective effects of FGF21 were abolished by co-treatment with PPARδ inhibitor (GSK0660), indicating FGF21 attenuated ER stress-induced ferroptosis by dependent on FGFR1/PPARδ signaling pathway. ConclusionOur study reveals that FGF21 protects against pulmonary I/R injury via inhibiting ER stress-induced ferroptosis though FGFR1/PPARδ signaling pathway. Boosting endogenous FGF21 or the administration of recombinant FGF21 could be promising therapeutic strategies for pulmonary IRI.

FGF21 modulates immunometabolic homeostasis via the ALOX15/15-HETE axis in early liver graft injury

Fibroblast growth factor 21 (FGF21) is essential for modulating hepatic homeostasis, but the impact of FGF21 on liver graft injury remains uncertain. Here, we show that high FGF21 levels in liver graft and serum are associated with improved graft function and survival in liver transplantation (LT) recipients. FGF21 deficiency aggravates early graft injury and activates arachidonic acid metabolism and regional inflammation in male mouse models of hepatic ischemia/reperfusion (I/R) injury and orthotopic LT. Mechanistically, FGF21 deficiency results in abnormal activation of the arachidonate 15-lipoxygenase (ALOX15)/15-hydroxy eicosatetraenoic acid (15-HETE) pathway, which triggers a cascade of innate immunity-dominated pro-inflammatory responses in grafts. Notably, the modulating role of FGF21/ALOX15/15-HETE pathway is more significant in steatotic livers. In contrast, pharmacological administration of recombinant FGF21 effectively protects against hepatic I/R injury. Overall, our study reveals the regulatory mechanism of FGF21 and offers insights into its potential clinical application in early liver graft injury after LT.